Helton José Alves

Environmental, economic and social impact of aviation biofuel production in Brazil

The Brazilian aviation industry is currently developing biofuel technologies that can maintain the operational and energy demands of the sector, while reducing the dependence on fossil fuels (mainly kerosene) and greenhouse gas emissions. The aim of the current research was to identify the major environmental, economic and social impacts arising from the production of aviation biofuels in Brazil. Despite the great potential of these fuels, there is a significant need for improved routes of production and specifically for lower production costs of these materials. In addition, the productive chains of raw materials for obtaining these bioenergetics can be linked to environmental impacts by NOx emissions, extensive use of agricultural land, loss of wildlife and intensive water use, as well as economic, social and political impacts.

Effect of shrimp shells milling on the molar mass of chitosan

Shrimp shells are a raw material rich in chitin, a precursor of chitosan biopolymer. The variables of processing (demineralization, deproteination and deacetylation) can be manipulated to determine the main characteristics of chitosan, the degree of deacetylation (DD), and average molar mass. This study evaluated the influence of one of the unit operations of shrimp shell physical processing, the milling, on the final product characteristic, chitosan. After different milling conditions, the raw material was subjected to standard chemical processing for chitin extraction, followed by deacetylation to obtain chitosan, which is characterized by 1H NMR, SEM, XRD, N2 physisorption (BET) and viscometry. The results indicated that the milling time of the raw material can be manipulated to increase the material depolymerization, significantly influencing the molecular weight reduction of chitosan a desirable feature for many applications of this biopolymer, and usually obtained by complex chemical and enzymatic methods.

Use of rice husk in waste cooking oil pretreatment

ABSTRACT Since industrial wastes are increasing, the development of studies to find ways for their use is urgent. Waste cooking oil is an important source for the production of biodiesel, one of the main biofuels in Brazil. However, during cooking, the oil undergoes conditions that change its properties and decrease its quality, such as its acidity value. Current research treats waste cooking oil by the adsorption process using rice husk, an agro-industrial waste, and activated carbon to compare results. The potential of the adsorbents to remove free fatty acids in waste cooking oil has been investigated by the batch technique, evaluating different operating conditions of temperature, adsorbent mass and agitation. Adsorbents were characterized by nitrogen physisorption, scanning electron microscope, energy-dispersive spectroscopy and X-ray diffraction. The maximum result obtained for activated carbon at acidity reduction was 63%, using 22.4°C, 169.64 rpm and 3.39 g of adsorbent mass. Already, using the rice husk the percentage of removal was the same, 63% using 22.4°C, 80.36 rpm and 1.61 g of adsorbent, however in shorter times. The results prove that the application of the rice husk for this purpose is advantageous, for being a low-cost material, available on a large scale and that provide results similar to activated carbon.

Charred shrimp shells treated with potassium fluoride used as a catalyst for the transesterification of soybean oil with methanol

A basic catalyst made of charred shrimp shells treated with potassium fluoride (KF) was employed in the transesterification reaction of soybean oil in the presence of methanol to produce methyl esters. The shells used here are wastes from freshwater shrimp farming in the western region of the state of Parana, Brazil, which are normally discarded in dumps/landfills and are a rich source of the biopolymer chitin (poly-β-1,4-N-acetyl-D-glucosamine). Charring of the shells (at 450 °C for 2 h) is aimed at partially eliminating rests of proteins and fibers, as well as acetyl groups (-CH3CO), carbon dioxide (-CO2) and water, causing the rearrangement of the chitin structure. The subsequent treatment of the shells with KF (impregnation and activation at 250 °C for 2 h) potentiated the basic sites on the catalyst surface, rendering it active in the transesterification reaction. The catalysts and shrimp shells were characterized by thermal gravimetric analysis, differential thermal analysis, X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, N2 physisorption (Braunauer, Emmet and Teller) (BET), and Hammett basicity. An experimental design was created to evaluate the effect of the following variables of the transesterification reaction:temperature, catalyst weight ratio, and molar ratio of oil:alcohol. The results indicate that the treatment with KF increased the basicity of the catalyst. The highest conversion into methyl esters obtained with the experimental design was 86.3%, using an oil:alcohol molar ratio of 1:9, 3.0% (w/w) of catalyst, 85 °C, and 3 h of reaction. Leaching tests indicated that, after 10 h of refluxing in methanol, a conversion rate of 52.4% was achieved using the catalyst leached in optimized conditions. Kinetic studies showed that chemical equilibrium was established after 8 h of reaction, reaching a conversion rate of 96.7%, which reveals the potential of the catalyst to produce methyl esters (biodiesel).

Development of Chitosan Membranes as a Potential PEMFC Electrolyte

Commercial chitosan and chitosan extracted from shrimp shells are being used to design membranes to be tested as low cost electrolyte in PEM fuel cells. This study investigated the influence of the deacetylation degree (DD) and molar mass (MV) of the chitosans used in the composition of membranes on its performance regarding to proton conductivity and other properties. Preliminary results indicate that the chitosan extracted from shrimp shells generated membranes with promising properties such as proton conductivity, which demonstrated to be even a 100 times higher than those shown by commercial chitosan membranes. The significant increase in proton conductivity can be associated with the higher number and availability of amino groups (–NH2) in the chitosan produced in the laboratory, which presents higher DD and lower MV. It is believed that the properties of chitosan can be manipulated in such a way that it would be possible to obtain proton conductivity values closer to that presented by Nafion®.

Evaluation of hybrid neutralization/biosorption process for zinc ions removal from automotive battery effluent by dolomite and fish scales

ABSTRACT This work focused in the evaluation of Oreochromis niloticus fish scales (FS) as biosorbent material in the removal of Zn from a synthetic effluent based on automotive battery industry effluent and, further, a hybrid neutralization/biosorption process, aiming at a high-quality treated effluent, by a cooperative use of dolomite and FS. For this, a physicochemical and morphological characterization (i.e. SEM–EDX, FTIR, XRD, and TXRF) was performed, which helped to clarify a great heterogeneity of active sites (phosphate, carbonate, amide, and hydroxyl) on the biosorbent; also the inorganic constituents (apatites) leaching from the FS was identified. Biosorption results pointed out to a pH-dependent process due to changes in the functional group’s anionic character (i.e. electrostatic interactions), where an initial pH = 3 favored the Zn uptake. Kinetic and equilibrium studies confirmed the heterogeneous surface and cooperative sorption, wherein experimental data were described by Generalized Elovich kinetic model and the favorable isotherm profile by Langmuir–Freundlich isotherm ( = 15.38 mg g–1 and ). Speciation diagram of Zn species along with the leached species demonstrated that, for the studied pH range, the biosorption was the most likely phenomena rather than precipitation. Finally, the hybrid neutralization/biosorption process showed great potential since both the Zn concentration levels and the pH reached the legislation standards (CZn = 4 mg L–1; pH = 5). Hence, based on the characterization and biosorption results, a comprehensive evaluation of the involved mechanisms in such complex system helped to verify the prospective of FS biosorbent for the Zn treatment from solution, in both individual and hybrid processes.

Evaluation of different adsorbents for acidity reduction in residual oils

ABSTRACT This work aims to evaluate the adsorption potential of bentonite and sugarcane bagasse clay for the reduction of free fatty acids in cooking oil through batch technique, experimental planning with different operating conditions (temperature, adsorbent mass and agitation). After were carried out kinetic studies and thermodynamic studies. Thus, both adsorbents were characterized by nitrogen dispersion, scanning electron microscopy with coupled energy dispersion spectroscopy. The sugarcane bagasse provided higher reductions compared to the bentonite clay, 58 and 50%, respectively. In the kinetic studies, it was observed that the pseudo-secunda model for both materials. Among the isotherms studied, the Langmuir model was better adjusted for sugarcane bagasse and Freundlich for bentonite clay. Thermodynamic parameters indicated spontaneous and endothermic adsorption at temperatures of 18°C, 20°C and 25°C. Both materials showed an advantageous result with the reduction to the adsorption of free fatty acids in the residual oil, considering that they are low-cost materials, their pre-treatment is simple from the operational point of view and their physical and chemical characteristics are favorable to the adsorption process, sugarcane bagasse contains about 42% hemicellulose, which is a hydroxyl-rich material that attracts the H+ ions from the medium.